When you choose Help > InDesign Help (or press F1), you may or may not be getting the most up-to-date help topic. In some cases, the web version of Help includes additional information not found in the in-product help. In other cases, users have left useful comments. The GREP search topic includes both additional information and commenting.
Search using GREP expressions
Feel free to leave comments in web help (also called LiveDocs Help). And drop me a note if you think any topic needs to be reworked.
Someone mentioned in a user forum that he thinks en dashes surrounded by spaces ( – ) look better than em dashes (—) in sentences. That’s a matter of personal taste, but if you do go with the en dash, be aware that the en dash may wrap incorrectly when text reflows.
To avoid this problem, insert a hard space (Type > Insert White Space > Nonbreaking Space) before the en dash. A nonbreaking space essentially joins the dash with the preceding word.